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      <title>异常 - 交互式测验</title>
      <style>
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          margin: 0;
          padding: 20px;
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          width: 100%;
          max-width: 700px;
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        .quiz-header {
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          color: white;
          padding: 20px 30px;
          text-align: center;
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        .quiz-header h1 {
          margin: 0;
          font-size: 24px;
          font-weight: 700;
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        .quiz-header p {
            margin: 5px 0 0;
            font-size: 14px;
            opacity: 0.9;
        }

        .quiz-body {
          padding: 30px;
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        .progress-bar {
            display: none; /* 隐藏进度条 */
            width: 100%;
            background-color: #e0e0e0;
            border-radius: 5px;
            height: 10px;
            margin-bottom: 20px;
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        #progress-indicator {
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            border-radius: 5px;
            transition: width 0.3s ease;
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        #question-container {
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        #question-text {
          font-size: 18px;
          font-weight: 500;
          line-height: 1.6;
          margin-bottom: 25px;
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        .options-list {
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          padding: 0;
          margin: 0;
        }

        .option-item {
          background-color: #f8f9fa;
          border: 1px solid #dee2e6;
          border-radius: 8px;
          padding: 15px;
          margin-bottom: 12px;
          cursor: pointer;
          transition: background-color 0.2s ease, border-color 0.2s ease;
        }

        .option-item:hover {
          background-color: #e9ecef;
        }
        
        .option-item.selected {
            background-color: #d1e7fd;
            border-color: #4a90e2;
        }

        .quiz-footer {
          padding: 20px 30px;
          display: flex;
          justify-content: space-between; /* 将按钮分布在两侧 */
          align-items: center;
          min-height: 65px; /* Reserve space */
        }

        .nav-btn {
          background-color: #4a90e2;
          color: white;
          border: none;
          border-radius: 8px;
          padding: 10px 20px;
          font-size: 16px;
          font-weight: 500;
          cursor: pointer;
          transition: background-color 0.2s ease, transform 0.2s ease;
          box-shadow: 0 4px 12px rgba(0,0,0,0.15);
        }
        
        #next-btn {
            background-color: #28a745;
        }

        .nav-btn:hover {
          background-color: #357abd;
          transform: scale(1.05);
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        .nav-btn:disabled {
            background-color: #a0c3e8;
            cursor: not-allowed;
            opacity: 0.7;
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        #result-container {
            border-top: 1px solid #eee;
        }
        
        .result-box {
            border-radius: 8px;
            padding: 20px;
            margin-top: 20px;
        }
        
        .result-box.correct {
            background-color: #d4edda;
            border: 1px solid #c3e6cb;
            color: #155724;
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        .result-box.incorrect {
            background-color: #f8d7da;
            border: 1px solid #f5c6cb;
            color: #721c24;
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        .result-box h3 {
            margin-top: 0;
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        .explanation-text {
            margin-top: 15px;
            line-height: 1.7;
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        .source-text {
            font-style: italic;
            font-size: 14px;
            margin-top: 15px;
            color: #555;
        }

        
        .final-score-container {
            padding: 40px;
            text-align: center;
        }
        .final-score-container h2 {
            margin-top: 0;
            margin-bottom: 30px;
        }
        .score-summary {
            display: flex;
            justify-content: center;
            gap: 20px;
            margin-bottom: 40px;
            flex-wrap: wrap;
        }
        .score-card {
            background-color: #f8f9fa;
            border-radius: 12px;
            padding: 20px;
            width: 180px;
            box-shadow: 0 4px 12px rgba(0,0,0,0.05);
            border: 1px solid #e9ecef;
        }
        .score-card h3 {
            margin: 0 0 10px;
            font-size: 16px;
            font-weight: 500;
            color: #555;
        }
        .score-card p {
            margin: 0;
            font-size: 28px;
            font-weight: 700;
            color: #333;
        }
        .score-details table {
            width: 100%;
            font-size: 16px;
        }
        .score-details td {
            padding: 4px 0;
        }
        .score-details td:last-child {
            text-align: right;
            font-weight: 700;
        }
        .report-actions button {
            background-color: #fff;
            border: 1px solid #ccc;
            border-radius: 8px;
            padding: 12px 25px;
            font-size: 16px;
            cursor: pointer;
            margin: 0 10px;
            transition: background-color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
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        .report-actions button:hover {
            background-color: #f1f1f1;
            border-color: #bbb;
            transform: translateY(-2px);
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        .report-actions button.primary {
            background-color: #28a745;
            color: white;
            border-color: #28a745;
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        .report-actions button.primary:hover {
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        .hint-container {
            background-color: #e0f7fa;
            border: 1px solid #b2ebf2;
            border-radius: 8px;
            padding: 15px;
            margin-top: 20px;
            color: #006064;
            font-size: 15px;
            line-height: 1.6;
            display: none; /* 默认隐藏 */
        }
      </style>
    </head>
    <body>
      <div class="main-wrapper">
          <div class="quiz-container">
            <div class="quiz-header">
              <h1>异常 - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
            </div>
            <div id="quiz-content">
                <div class="quiz-body">
                    <div class="progress-bar">
                        <div id="progress-indicator"></div>
                    </div>
                    <div id="question-container">
                      <p id="question-text"></p>
                      <ul class="options-list" id="options-list"></ul>
                    </div>
                    <div id="result-container"></div>
                    <div id="hint-container" class="hint-container"></div>
                </div>
                <div class="quiz-footer" id="quiz-footer">
                  <button id="prev-btn" class="nav-btn">上一题</button>
                  <button id="hint-btn" class="nav-btn" style="background-color: #ffc107; color: #333; box-shadow: 0 4px 12px rgba(255,193,7,0.3);">提示</button>
                  <button id="next-btn" class="nav-btn">下一题</button>
                </div>
            </div>
          </div>
      </div>

      <script>
        const quizData = [
  {
    "question": "根据文档，以下哪项描述最准确地区分了编译时异常（Checked Exception）和运行时异常（Unchecked Exception）？",
    "options": [
      "运行时异常是由外部环境因素（如网络中断）引起的，而编译时异常是程序逻辑错误。",
      "编译时异常继承自`Error`类，而运行时异常继承自`Exception`类。",
      "编译时异常必须在编码时显式处理（通过try-catch或throws），否则无法通过编译；而运行时异常则不需要。",
      "所有异常都必须在编译时处理，否则程序会崩溃。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "文档明确指出，编译时异常（Checked Exception）是在编译阶段由编译器检测出来的，必须显式处理。而运行时异常（Unchecked Exception）是在程序运行时由JVM检测出来的，不需要在程序中进行显式处理。它们通常是由程序逻辑错误（如空指针）导致的。",
    "source": "文档中「异常的分类」-「1. 编译时异常（Checked Exception）」与「2. 运行时异常（Unchecked Exception）」部分",
    "hint": "思考一下这两种异常是在哪个阶段被检测出来的，以及编译器对它们的要求有何不同。"
  },
  {
    "question": "在Java的`try-catch-finally`结构中，关于`finally`块的执行时机，以下哪个说法是正确的？",
    "options": [
      "仅当`try`块中发生异常并被`catch`块成功捕获时执行。",
      "仅当`try`块中的代码顺利执行，没有发生任何异常时执行。",
      "无论`try`块中是否发生异常，`finally`块中的代码总会被执行。",
      "只有在`catch`块中重新抛出异常时，`finally`块才会被执行。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "文档中强调，`finally`块用于定义在`try-catch`结构中必须执行的代码块。它的核心特性是“无论是否发生异常都会执行”，这使得它非常适合用于执行资源释放等清理工作。",
    "source": "文档中「Java 异常处理机制」-「2. finally 块的作用和用法」部分",
    "hint": "文档中提到`finally`块通常用于“释放资源或清理工作”，想一想这类操作的执行时机要求。"
  },
  {
    "question": "Java 7 引入的 `try-with-resources` 语句主要解决了什么问题？",
    "options": [
      "它允许在一个`catch`块中处理多种不同类型的异常。",
      "它用于创建和管理自定义的异常类。",
      "它自动管理和关闭实现了 `AutoCloseable` 接口的资源，简化了资源释放操作，避免了资源泄露。",
      "它显著提高了异常捕获和处理的性能。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "`try-with-resources` 语句是一种语法糖，专门用于简化资源管理。对于实现了 `AutoCloseable` 接口的资源（如文件流），在`try`块结束时，Java会自动调用其`close()`方法，从而避免了在`finally`块中编写冗长的资源关闭代码，有效防止了资源泄露。",
    "source": "文档中「Java 异常处理机制」-「3. try-with-resources 语句的介绍」部分",
    "hint": "这个语法特性与资源管理密切相关，特别是那些使用后需要被“关闭”的资源。"
  },
  {
    "question": "在Java的异常类层次结构中，所有异常（Exception）和错误（Error）的共同根类是什么？",
    "options": [
      "Exception",
      "Object",
      "Error",
      "Throwable"
    ],
    "correctAnswerIndex": 3,
    "explanation": "文档的类层次结构图和描述都明确指出，`Throwable`是Java中所有可抛出问题的根类。它有两个主要的直接子类：`Exception`（代表程序可处理的异常）和`Error`（代表通常不应由程序捕获的严重问题）。",
    "source": "文档中「异常类层次结构」-「1. Throwable 类」部分",
    "hint": "在异常继承树的顶端，是哪一个类派生出了`Exception`和`Error`？"
  },
  {
    "question": "当一个方法内部发生异常但没有被`try-catch`块捕获时，根据Java的异常传播机制，接下来会发生什么？",
    "options": [
      "程序会立即终止，并打印堆栈跟踪信息。",
      "异常会被自动忽略，程序继续从下一行代码开始执行。",
      "异常会沿着方法调用链向上传播，交给调用该方法的上层方法去处理。",
      "Java虚拟机会自动将该异常转换为一个 `Error`。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "Java的异常传播机制规定，如果当前方法不处理异常，异常对象会沿着方法调用栈（call stack）反向传播，直到找到一个能够处理该异常的`catch`块，或者直到传播到最顶层的`main`方法仍未被处理，此时程序才会终止。",
    "source": "文档中「异常的传播机制」-「2. 异常的传递」部分",
    "hint": "想一想方法调用是如何形成一个“链条”的，异常在这个链条上是如何移动的。"
  },
  {
    "question": "在创建自定义异常时，文档建议开发者定义的异常类通常应该继承自以下哪两个类之一？",
    "options": [
      "`Throwable` 或 `Error`",
      "`Object` 或 `Throwable`",
      "`Error` 或 `RuntimeException`",
      "`Exception` 或 `RuntimeException`"
    ],
    "correctAnswerIndex": 3,
    "explanation": "文档中明确指出：“自定义异常类通常继承自Java标准库中的 `Exception` 或 `RuntimeException` 类。” 继承自 `Exception` 会创建编译时异常（Checked Exception），而继承自 `RuntimeException` 会创建运行时异常（Unchecked Exception）。",
    "source": "文档中「自定义异常」部分",
    "hint": "自定义异常是为了处理特定的业务场景，思考一下这些场景应该被定义为需要强制处理的异常，还是可选处理的异常。"
  },
  {
    "question": "文档中提到了一条重要的异常处理策略：“捕获精确的异常”。以下哪项是遵循该策略的最佳实践？",
    "options": [
      "catch (Throwable t) { ... }",
      "catch (Exception e) { ... }",
      "catch (IOException | SQLException e) { ... }",
      "在一个空的 catch 块中捕获所有异常，以防止程序崩溃。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "捕获精确的异常，如`IOException`或`SQLException`，可以使代码意图更清晰，并允许针对不同类型的错误执行不同的恢复逻辑。而捕获宽泛的`Exception`或`Throwable`会把预料之外的运行时错误（如`NullPointerException`）和预期的异常混为一谈，增加了调试难度。空的`catch`块更是应该极力避免的坏习惯。",
    "source": "文档中「异常的处理策略和建议」-「1. 捕获精确的异常」部分",
    "hint": "“精确”的反义词是“宽泛”或“笼统”。在`catch`语句中，哪个选项最能体现处理的针对性？"
  }
];
        console.log("Quiz Data:", JSON.parse(JSON.stringify(quizData))); // 添加这行用于调试，以可展开的JSON格式输出
        
        let currentQuestionIndex = 0;
        let score = 0;
        // 存储每个问题的回答状态
        const userAnswers = new Array(quizData.length).fill(null); 

        const questionTextEl = document.getElementById('question-text');
        const optionsListEl = document.getElementById('options-list');
        const resultContainerEl = document.getElementById('result-container');
        const quizContentEl = document.getElementById('quiz-content');
        const progressIndicatorEl = document.getElementById('progress-indicator');
        const prevBtn = document.getElementById('prev-btn');
        const nextBtn = document.getElementById('next-btn');
        const hintBtn = document.getElementById('hint-btn');
        const hintContainerEl = document.getElementById('hint-container');

        function loadQuestion() {
          resultContainerEl.innerHTML = '';
          optionsListEl.innerHTML = '';
          hintContainerEl.style.display = 'none'; // 隐藏提示
          
          if (currentQuestionIndex >= quizData.length) {
            showFinalScore();
            return;
          }

          updateProgress();

          const currentQuestion = quizData[currentQuestionIndex];
          questionTextEl.textContent = `(${currentQuestionIndex + 1}/${quizData.length}) ${currentQuestion.question}`;
          
          currentQuestion.options.forEach((optionText, index) => {
            const li = document.createElement('li');
            li.className = 'option-item';
            li.textContent = optionText;
            li.dataset.index = index; // Store index in a data attribute
            // 如果这道题已经回答过，恢复状态
            if (userAnswers[currentQuestionIndex] !== null) {
                if (index === userAnswers[currentQuestionIndex]) {
                    li.classList.add('selected');
                }
            }
            optionsListEl.appendChild(li);
          });

          // 如果已经回答过，直接显示结果
          if (userAnswers[currentQuestionIndex] !== null) {
              const isCorrect = userAnswers[currentQuestionIndex] === currentQuestion.correctAnswerIndex;
              showResult(isCorrect, currentQuestion);
          }
          
          updateNavigationButtons();
          updateProgress();
        }

        function selectOption(optionIndex) {
            userAnswers[currentQuestionIndex] = optionIndex;
            const currentQuestion = quizData[currentQuestionIndex];
            const isCorrect = optionIndex === currentQuestion.correctAnswerIndex;

            // 重新计算分数
            score = userAnswers.reduce((acc, answer, index) => {
                return answer === quizData[index].correctAnswerIndex ? acc + 1 : acc;
            }, 0);

            showResult(isCorrect, currentQuestion);
            updateNavigationButtons();
        }
        
        function updateProgress() {
            const answeredQuestions = userAnswers.filter(answer => answer !== null).length;
            const progressPercentage = (answeredQuestions / quizData.length) * 100;
            progressIndicatorEl.style.width = `${progressPercentage}%`;
        }
        
        function updateNavigationButtons() {
            prevBtn.style.display = 'block';
            nextBtn.style.display = 'block';
            hintBtn.style.display = 'block'; // 显示提示按钮

            prevBtn.disabled = currentQuestionIndex === 0;
            nextBtn.disabled = false; // 最后一题时，下一题按钮不禁用，而是用于显示报告
            nextBtn.textContent = (currentQuestionIndex === quizData.length - 1) ? '查看报告' : '下一题';
            
            // 如果当前问题没有提示，则禁用提示按钮并隐藏提示内容
            if (!quizData[currentQuestionIndex].hint) {
                hintBtn.disabled = true;
                hintContainerEl.style.display = 'none';
                hintContainerEl.textContent = ''; // 清除旧的提示内容
            } else {
                hintBtn.disabled = false;
            }
        }

        function showResult(isCorrect, questionData) {
            resultContainerEl.innerHTML = ''; // 清空之前的结果
            const resultBox = document.createElement('div');
            resultBox.className = `result-box ${isCorrect ? 'correct' : 'incorrect'}`;
            
            let html = `<h3>${isCorrect ? '回答正确！' : '回答错误'}</h3>`;
            if (!isCorrect) {
                html += `<p><strong>正确答案是：</strong> ${questionData.options[questionData.correctAnswerIndex]}</p>`;
            }
            html += `<div class="explanation-text">${questionData.explanation}</div>`;
            html += `<div class="source-text">来源: ${questionData.source}</div>`;
            
            resultBox.innerHTML = html;
            resultContainerEl.appendChild(resultBox);

            // 禁用所有选项的点击事件，并高亮正确/错误答案
            Array.from(optionsListEl.children).forEach((child, index) => {
                child.style.pointerEvents = 'none';
                // 高亮正确答案
                if (index === questionData.correctAnswerIndex) {
                    child.classList.add('correct'); // 需要添加CSS样式
                    child.style.backgroundColor = '#d4edda';
                    child.style.borderColor = '#c3e6cb';
                }
                // 如果选错了，高亮错误选项
                if (!isCorrect && index === userAnswers[currentQuestionIndex]) {
                    child.classList.add('incorrect'); // 需要添加CSS样式
                    child.style.backgroundColor = '#f8d7da';
                    child.style.borderColor = '#f5c6cb';
                }
            });
        }

        function goToNextQuestion() {
            if (currentQuestionIndex < quizData.length - 1) {
                currentQuestionIndex++;
                loadQuestion();
            } else {
                showFinalScore();
            }
        }

        function goToPreviousQuestion() {
            if (currentQuestionIndex > 0) {
                currentQuestionIndex--;
                loadQuestion();
            }
        }
        
        function showHint() {
            const currentQuestion = quizData[currentQuestionIndex];
            if (currentQuestion.hint) {
                hintContainerEl.textContent = currentQuestion.hint;
                hintContainerEl.style.display = 'block';
            } else {
                hintContainerEl.style.display = 'none';
            }
        }

        function showFinalScore() {
            document.querySelector('.quiz-body').style.display = 'none';
            document.getElementById('quiz-footer').style.display = 'none';

            const correctCount = score;
            const totalQuestions = quizData.length;
            const answeredCount = userAnswers.filter(a => a !== null).length;
            const wrongCount = answeredCount - correctCount;
            const skippedCount = totalQuestions - answeredCount;
            const accuracy = totalQuestions > 0 ? Math.round((correctCount / totalQuestions) * 100) : 0;
            const errorRate = totalQuestions > 0 ? Math.round((wrongCount / totalQuestions) * 100) : 0;

            const finalScoreHtml =
                '<div class="final-score-container">' +
                '<h2>答题报告</h2>' +
                '<div class="score-summary">' +
                '<div class="score-card">' +
                '<h3>得分</h3>' +
                '<p>' + correctCount + ' / ' + totalQuestions + '</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>正确率</h3>' +
                '<p>' + accuracy + '%</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>错误率</h3>' +
                '<p>' + errorRate + '%</p>' +
                '</div>' +
                '<div class="score-card score-details">' +
                '<table>' +
                '<tr><td>正确</td><td>' + correctCount + '</td></tr>' +
                '<tr><td>错误</td><td>' + wrongCount + '</td></tr>' +
                '<tr><td>未答</td><td>' + skippedCount + '</td></tr>' +
                '</table>' +
                '</div>' +
                '</div>' +
                '<div class="report-actions">' +
                '<button id="review-btn">回顾测验</button>' +
                '<button class="primary" onclick="location.reload()">再试一次</button>' +
                '</div>' +
                '</div>';

            let reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }
            quizContentEl.insertAdjacentHTML('beforeend', finalScoreHtml);
            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  